I'm making a frame bag for my new (to me) mountain bike. It's a disk brake bike so I can't mount any decent racks to it without doing something that'll likely be annoying. (Or spending significantly more money on a rack than I'd like.) So I figured I'd try out a frame bag. Not wanting to buy one (I'd be very... very annoyed by the fact it wasn't made for this specific bike and only "kinda" fits) I'll make one. The sewing should be pretty easy.

Anyway, I've thought of a few features I'd enjoy and am implementing.

Outer U-Lock sleeve/pocket with velcro strap to hold the lock in place.

Two main compartment interior with an aluminum piece separating the two. The aluminum piece serves two jobs. One, it serves as a mounting place to screw into the bottle cage bosses on the downtube and seat tube and two, it serves as a stable shelf for the top compartment so that heavy things won't push down on the relatively fragile fabric compartment separator. I mainly did this because I wanted to store my chain lock in the bottom compartment and I didn't want it bouncing everywhere.

Lastly, I've implemented an small interior pocket for storing small items like tools and tubes. This pocket has a velcro closure flap.

The overall bag has two zippers, one following the top tube, the other at 90 degrees about 2 inches away from the seat tube. This will allow you to access both compartments individually and also fold the entire side of the bag out so you can access everything. I don't have waterproof zippers, so I'm just putting a flap over them (like in a winter shell/rain shell.) (And honestly chunky plastic zippers are better for this application. Less likely to get caught on things. I believe I have #8 or #10 zippers (BIG ass zippers, think duffel bag zippers.)

I'm using duck cloth for the outer fabric. Seeing as this is the first frame bag I'm making, I'm not going to spring for cordura or anything expensive yet. Maybe if I make another. I'm also lining the inside of the bag with wool (it's what I had and got it on sale) The bag needs a lining because I'm using interfacing to make the fabric less flexible, so the interfacing needs fabric on each side to hide it.


Is there anything else that you guys would put on a frame bag if you were to make one? I'm still in the cutting out fabric phase, so I can still make adjustments.

Since you're securing it with screws, that alleviates one of my major complaints about bike bags: I want to be able to easily remove the entire bag, and carry it with me, using the securely-attached, comfortable HANDLE!

How about adding an outer pocket for your phone? Something that will close and protect it, but doesn't require rooting around in the main compartment to answer a call, or to get the phone out to capture a crime scene video?

I would want some sort of clasp, inside, to hold keys, so they don't fall to the bottom of the bag.

I hope we'll get to see the final product!

Hey thanks for the advice! I don't think this is going to be an easily removeable bag, so I'm not going to worry about the handle. However the key and phone thing is nice. When I'm commuting (in the winter I'll use this bike sometimes) the phone and keys are often in my pocket, but if I'm off mountain biking it'd be nice to have a place to store them.

The bag will also be attached to the bike via the traditional loops of fabric with velcro or straps on the top tube and head tube.

I'll definitely post pictures when I'm done. I've already cut out the majority of the fabric, so I have to finish it now or I'm just wasting money.

I'd want it as accessible as possible from the saddle -- although stopped would be fine, not necessarily accessible while riding. I'd prefer an outside pouch angled toward the rider while seated, although it may be less secure so a good closure and/or flap might be appropriate.

One-handed operation so the zippers and closures would need to be really good and smooth, non-binding.

Outside pouches for quick access might be best with an elastic closure, depending on anticipated usage. A slip pouch might be handy, depending on whether I also used a handlebar bag with map pouch in the top like my old Kirtland Tour Pak.

I really dislike Velcro for anything other than arranging the positions of adjustable dividers. Velcro for temporary/quick attachable-detachable mounts would be okay. It's my pet peeve with camera bags. I won't carry a bag that uses Velcro for closures on main compartments and outer pouches. Besides being noisy, they're difficult to operate one-handed, inevitably trap stray fibers and gunk that causes the closures to become less secure with age, and just generally seem like a cheap and nasty solution that could be better handled with other types of closures. That's one reason I generally prefer Domke camera bags, and look for a similar design in any bag. Billingham and similarly designed (and expensive) classic bags also use closures other than Velcro.

One reason I like my cheap trunk bag - actually a rolling beer cooler/picnic bag - is because it uses good sturdy, smooth zippers for the main compartment and outer pouch. There's also a mesh/net elastic pouch on the outside but I seldom use it.

Sounds like a fun project, looking forward to seeing what you make.

@canklecat : Thanks for the advice. I have snaps if I want to use them, but I was thinking velcro is nice because things can slip out of snapped pockets. (Unless you have a LOT of snaps.) I do also get annoyed by velcro, but mainly because of bad implementation. Sewed correctly it should be fine. (Plus snaps could be noisy when riding, where as velcro would be silent.) I honestly could just use a smaller #5 zipper for the inside pocket...Hmmm... There are various qualities of velcro. Good velcro lasts a very long time while crappy velcro catches everything and doesn't last that long.

The zippers are really the best you can get for not catching. The molded plastic zippers fare the best in dirty conditions and in conditions where things can get caught in them. (Hence why they're often used in duffel bags and winter jackets.) Metal zippers are worst, followed by the plastic zippers with tiny teeth. (In my opinion.) (And plastic doesn't rust!)

I like your idea of an accessible pocket while riding. Good for snacks. Maybe I'll put a couple of pockets along the top of the bag on the non-zipper side.

Good move, cutting it all out. That way you're committed! I agree with Canklecat, too, about making it stiff and secure enough that the zippers can be operated with one hand. I have a bag of similar shape that is too ...flimsy to allow opening and closing the zipper with one hand, so I pretty much have to stop and assume a certain position to get both hands involved.

For the exterior pockets, consider using bungee cord to hold things like your phone, so you can position the phone and the cord to allow for a charging cable or headphones to be used without risking damage. One of the good things about making your own gear is that you can customize things like that. All sorts of things you could do, while you're at it. Since the bag won't be readily removable, I'd avoid using Velcro to secure it to the top tube. Use something more secure, and less prone to eventual failure. Maybe you could incorporate nylon straps with those plastic buckles that snap apart, where needed.

If you're going to carry significant weight, consider extending the straps that secure the bag to the top tube all the way around the bag, so the straps are carrying the load, and not the stitching.

Oooo bungie straps with buttons. I like that idea. Quiet and one handed. (A bungie "loop" that wraps around a button.)

I've been debating the best way to attach the bag to the top tube. Unfortunately all of my cables run along the top tube on this bike, so I can't have bulky things up there. If I wrap nylon straps around the whole bag, when I cinch them tight it'll pull UP on the bottom of the bag, which I don't want. In all honesty, this bag will be sitting entirely on the frame, so it'll support any heavy weight. (In theory.) I was just going to do tubes of fabric with velcro because that's what the most of the frame bags I've seen use. (Any they probably have made a lot more than I have. )

If the bag is going to sit on the frame, then everything in the bag is going to take all the vibration and punishment that the frame gets, too. Maybe that's an issue, and maybe not, but something to consider. You wouldn't, necessarily, have to cinch the straps up, tight. Just have them take the bulk of the weight. Give it some thought. You'll figure out the best way to deal with it. Just throwing out ideas.

Another thing to consider is dirt. And, water. Maybe a couple of drain holes, near the bottom of the bag, would be a good idea, to provide an escape point for the inevitable grit and water that will find their way into the bag. Not sure how to go about keeping the material from fraying. Maybe really small grommets, like for shoestrings? If the bag is secured by all the bottle bracket screws, it's going to be a pain to remove to clean it out, so think about providing for that, now. You could just wash it out with a garden hose, I suppose.

I'm unclear on the concept for a mountain bike. Will this be used for touring or day packing? Then, a good idea.

For single track riding, everything goes into a Camelbak Mule. I don't need to access anything while riding except water...

Yes.

Honestly the bag is mostly for when I must commute in the winter with it. I despise wearing a backpack with my locks and stuff in it (heavy chain and U lock).

And yes, bikepacking as well. Otherwise the bag will be taken off.

How much to get one in Cuban Fiber?

Maybe it's just me, but I like it to be quick release as in a couple of buckles that you just slide in or out. That way you can just pull it off and take with you, and then put it back on without making a big production of it. The bag in that case needs a carry strap.

Ohhhh best idea ever. Magnets for pocket closures. Great idea.

I use a small frame bag on my roadie (on my third bag). +1 on the one-handed zipper. Also +1 on the easy access outer pocket. That is where I would like to put my hanky/nose-wiper thing. Also, if you're thinking of keeping it on the bike, perhaps a loop so the zippers can be locked with a small lock that you keep in the bag, or on one of the loops, or if you can figure out a way, have some sort of way to lock it with the same cable lock you'd use on the bike

Lock the zippers and thieves will rip or cut the bag.

+1 on the quick-access outer pocket. 8.75 for the design; eager to see pics of the finished product.

Ditto, the magnet closure tip for a quick access outer pouch. And maybe a second magnetic strip to hold the flap open as well as closed.

Reminds me, I recently received a pouch with a magnetic flap for a cell phone or small camera. Haven't used it yet.

I hate to be a downer, but as someone who's used a frame bag daily, for a couple of years, there is one thing I want to caution about while you design it. By far the biggest annoyance, and possible deal-killer, is if you make it too thick. You need to keep that in mind as you draw out the multiple layered compartments, extra liners, and so forth. I suggest building a temporary quick mock-up, stuff it with a typical load and tie it on and try a few long rides with it.

With just a full change of clothes and some incidentals, distributed through a large frame bag, I've found no problem at all. Adding some gloves, cloth hat, extra jersey or windbraker is pushing it, forcing me to ride bow-legged or rub my knees. More compartments, more bulk, even forcing some items to one side instead of the middle, might make it an untenable design.

I was thinking about that. I was shooting for 2.5 inches thick unpacked, but I may thin it down to 2 inches. I could also taper the entire bag so it's thin where my knees are. With the pockets and Ulock holder on the outside it's a bit thicker than I had originally intended. (It's not hard to change the thickness at this point.) However, I did put the Ulock holder as far back and down as possible, so it shouldn't even come in contact with my legs.

What would you suggest for thickness?

EDIT: I'm also trying to think of a way to cinch the bag... sideways, so you can pull it in toward itself. Nothing is jumping out at me.

I'm thinking magnets to hold it closed, then just use the steel frame to hold it open.

For me a fist width between the knees doesn't alter my pedaling. I'd say stuffed to six inches thick (in the middle) becomes uncomfortable. It probably varies according to the individual. Maybe shaping the whole thing so that it's tapered from the bottom to top would alleviate it.

Thanks, I'll keep that in mind. The easiest way to compress it would be to simply put a strap that goes horizontally across the inside, from one side to the other. Accessing it would be... difficult to say the least. Unless... I put a small zipped hole right above the strap so I could tighten the strap then zip the "hole" up. Complicated, but not impossible.

How about some reflective bits on the outside for increased visibility?